Developments toward Passive Variable Compliance for
Dynamic Legged Robots

Kevin C. Galloway
Advisor: Dr. Mark Yim
Department of Mechanical Engineering and Applied Mechanics
University of Pennsylvania

Abstract

Recent developments in dynamic legged locomotion have focused on encoding a substantial component of leg intelligence into passive compliant mechanisms. One of the limitations of this approach is reduced adaptability: the final leg mechanism usually performs optimally for a small range of conditions (i.e. a certain robot weight, terrain, speed, gait, and so forth). For many situations in which a small locomotion system experiences a change in any of these conditions, it is desirable to have a variable stiffness leg to tune the natural frequency of the system for effective gait control.

To date, the mechanical complexities of designing usefully robust tunable passive compliance into legs has precluded their implementation on practical running robots.  In this seminar, we present an overview of variable stiffness legs, and introduce new run-time tuning methods specifically for autonomous dynamic legged locomotion.    We also introduce a simple leg model that captures the spatial compliance of the unable leg and present preliminary experimental data on the advantages of variable passive compliant legs.  Lastly, we will discuss design rules, materials, and manufacturing methods that lead to robust passive compliant legs.

Thursday, August 6, 2 PM
337 Towne Building